Recurrent reflective synthetic filament yarn and method of producing the same

ABSTRACT

A recurrent reflective synthetic filament yarn is disclosed. The yarn is produced by the following process, including the steps of melt-spinning a mixture of glass beads and a synthetic fiber resin through a spinneret, said beads being vacuum-metalized with a material having a reflection function. The process further comprising the steps of positioning an electric field around the spinneret, and passing said filament through the electric field before said filament is solidified, whereby said glass beads in said filament rotate so that said metalized parts of the glass beads all point in a same direction.

[0001] Cross-Reference

[0002] This application is a Continuation-In-Part of copending U.S.application Ser. No. 10/150,697.

FIELD OF THE INVENTION

[0003] The present invention pertains, in general, to a reflective yarnand more particularly, the present invention relates to a recurrentreflective synthetic filament yarn including spherical glass beads thatare vacuum-metalized.

DESCRIPTION OF THE PRIOR ART

[0004] Generally, reflective materials having a reflective function arewidely used in safety applications for preventing accidents and securingsafe conditions, and demands for these reflective materials have beengrowing rapidly. For example, when a traffic policeman or a streetsweeper works at night, or when an elderly or very young person isexposed to vehicles at night, it is difficult for a driver to recognizethem, and so a loss of life may result. To reduce the risk, therefore,materials having the reflective function are applied to various trafficsigns, miscellaneous goods such as sportswear, sporting goods, and bags,and military recognition signs.

[0005] Meanwhile, various studies have been made of materials having ahigh reflective index as well as materials reflecting light. Forexample, a film or sheet shape of reflective materials are widely usedcommercially. However, a yarn shape of the reflective material is notcommercially produced, and thus the reflective material has hardly beenapplied to threads or textiles.

[0006] One example of conventional reflective fibers includes the filmor sheet shape of reflective materials as illustrated in FIGS. 1 and 2.However, the film or sheet shape of reflective materials are not fabricbut a film or sheet with or without a slit surface. In other words, areflective sheet is produced by coating an aluminum paste as areflective film on any one side of a thin synthetic resin sheet 60 toform a coating layer 70, as shown in FIG. 1. However, the reflectivesheet has disadvantages in that the reflective index and reflectionbrightness are practically weak because irregular reflection occursthrough the reflective film, thus the reflective sheet is not suitablefor commercial use, and reflection efficiency is rapidly reduced andcolor fastness to washing is low because the aluminum coating layer 70is easily removed from the synthetic resin sheet or easily damaged.

[0007] Furthermore, a reflective sheet may be produced by coating analuminum paste as a reflective film on any one side of a thin syntheticresin sheet 60 to form a coating layer 70 and coating a mixture oftransparent polyurethane and glass beads 40 on the aluminum coatinglayer 70, as shown in FIG. 2. However, the reflective sheet hasdisadvantages in that the synthetic resin sheet can be applied withlimits to clothes, have a poor texture and color fastness to washing,are reduced in workability, and are difficult to apply to embroideryyarn because the synthetic resin sheet is made of a hard material, suchas polyethylene terephthalate or polyvinyl chloride, even thoughrecurrent reflection can be feasible and reflection efficiency is good.

[0008] Synthetic resin fabric may be used instead of the synthetic resinsheet 60. However, the synthetic resin fabric is disadvantageous in thattexture, workability, and color fastness to washing are poor, and thesynthetic resin fabric cannot be widely applied even though reflectionefficiency is good.

[0009] With respect to the synthetic resin fabric, a reflective wovenfabric is disclosed in U.S. Pat. No. 4,187,332, which is produced bycoating reflective glass beads on a woven fabric and drying theresulting woven fabric.

[0010] Another example of the conventional reflective fibers is a slitreflective film or sheet, or a slit thread. In this respect, an aluminumpaste layer as a reflective layer is coated on any one side of a thinsynthetic resin film or sheet, a mixture of transparent polyurethane oran adhesive and glass beads is coated on the aluminum paste layer toproduce the reflective film or sheet, and the reflective film or sheetthus produced is longitudinally slit in such a way that a width of thereflective film or sheet is 0.25 to 0.37 mm for the narrow reflectivefilm or sheet, or 3 to 5 mm for the wide reflective film or sheet. Atthis time, the slit reflective film or sheet is doubled or twisted witha synthetic yarn to produce the slit thread. However, the slitreflective film or sheet, or the slit thread is readily broken becauseof the weak tensile strength thereof, and even if it is doubled ortwisted, its tensile strength is improved but its texture is poorer thanthat of fiber. Further, the slit reflective film or sheet, or the slitthread has disadvantages in that the aluminum paste layer or the glassbeads are easily separated from the synthetic resin film or sheet, orreadily damaged. Furthermore, the slit reflective film or sheet, or theslit thread is used as tapes or plates, but not as textiles. Strictlyspeaking, therefore, the slit reflective film or sheet, or the slitthread cannot be included in textiles.

[0011] For example, U.S. Pat. No. 4,336,092 discloses a process ofproducing a recurrent reflective thread including coating a thin filmtype of recurrent reflecting agent on a polyester film, slitting theresulting polyester film in a shape of thin strips, and mixing thestrips with other fibers. Additionally, U.S. Pat. No. 4,546,042 recitesa recurrent reflective thread produced by thinly cutting a sheet coatedwith a recurrent reflecting agent. However, it is impossible to use thisrecurrent reflective thread as a grey yarn for textiles.

[0012] Accordingly, there is a need to develop a filament yarn with anexcellent reflective function, which secures all functions required asthe filament yarn and is not produced by slitting a film or a sheet.

[0013] To meet the above need, Korean Pat. No. 10-355011 suggests theproduction of a recurrent reflective grey yarn according to a conjugatespinning process. According to this patent, a mixture of a recurrentreflective material including glass beads or mica, and a first polymermaterial capable of being spun is mixed with a second polymer materialcapable of being spun in a voluminal mixing ratio of 5 to 95 : 95 to 5,and then subjected to the conjugate spinning process to produce arecurrent reflective filament. However, this patent is disadvantageousin that a very complicated process is required to produce the recurrentreflective filament, and it is impossible to produce a thinner grey yarnthan a fishline through a technology as described in this patent, thusthe recurrent reflective filament cannot be applied as the grey yarn toan embroidery, a sewing, a weaving, and a knitting.

SUMMARY OF THE INVENTION

[0014] According to one aspect of the invention, a recurrent reflectivesynthetic filament yarn product is produced by the following processincluding the step of melt-spinning a mixture of glass beads and asynthetic fiber resin through a spinneret, the beads beingvacuum-metalized with a material having a reflection function. Theprocess further comprising the steps of positioning an electric fieldaround the spinneret, and passing the filament through the electricfield before the filament is solidified, whereby the glass beads in thefilament rotate so that the metalized parts of the glass beads all pointin a same direction.

[0015] According to a further aspect of the invention, the recurrentreflective synthetic filament yarn product has substantially 5 to 25 wt% of the glass beads.

[0016] According to a further aspect of the invention, each of the glassbeads is a spherical shape having a bead size of 30 to 50 μm, and arefractive index of 1.5 to 2.2.

[0017] According to a further aspect of the invention, the material hasthe reflective function is selected from the group consisting ofaluminum, nickel, and silver.

[0018] According to a second aspect of the invention, a recurrentreflective synthetic filament yarn is disclosed. The filament includesvacuum-metalizing spherical glass beads each having a bead size of 30 to50 μm and a refractive index of 1.5 to 2.2, wherein ¼ to ½ of an entiresurface area of the spherical glass beads are vacuum-metalized with amaterial, the material having a reflection function. The filamentincludes a synthetic resin. Five to 25 wt % of the filament is the glassbeads and 95 to 75 wt % of the filament being the synthetic fiber resin.The filament is melt-spun through a spinneret. The yarn is produced bythe following method including the steps of passing the filamentsthrough an electric field around the spinneret before the filaments aresolidified, so as to rotate the glass beads contained in the filamentssuch that metalized parts of the glass beads all point in a samedirection.

[0019] According to a further aspect of the invention, the spinnerethaving a nozzle and nozzle holes, and the method comprising the step ofinstalling a positive plate and a negative plate under the nozzle holesof the spinneret such that the positive plate and the negative plateface each other and are spaced from each other at an interval of one tofive mm. The method further comprising the step of applying a voltage of3000 to 20000 V and a current of three to five mA to the positive plateand negative plate, thereby forming the electric field.

[0020] According to a further aspect of the invention, the nozzle holesof the spinneret are aligned in one or two rows.

[0021] According to a further aspect of the invention, the methodcomprises the step of adding 0.2 to 0.5 wt % of dioctylphthalate as asoftener and 0.2 to 0.5 wt % of Ca antiadditive as a dispersing agentinto the synthetic fiber resin to uniformly mix the glass beads with thesynthetic fiber resin, to provide softness to the synthetic fiber resinduring the melt-spinning of a mixture of the glass beads and syntheticfiber resin, and to improve the softness of the recurrent reflectivesynthetic filament yarn.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

[0023]FIG. 1 schematically illustrates a mechanism of reflection oflight in a conventional reflective yarn;

[0024]FIG. 2 schematically illustrates a mechanism of reflection oflight in slit thread or fabric produced using the conventionalreflective yarn;

[0025]FIGS. 3 and 4 schematically illustrate a mechanism of reflectionof light in an omnidirectional reflective filament yarn (synthetic fiberfilament) according to the present invention;

[0026]FIG. 5 schematically illustrates a mechanism of reflection oflight in the omnidirectional reflective hollow filament yarn (syntheticfiber filament) according to the present invention;

[0027]FIG. 6 illustrates one filament of a recurrent reflective filamentyarn according to the present invention;

[0028]FIG. 7 illustrates the alignment of glass beads in each filamentof the recurrent reflective filament yarn according to the presentinvention;

[0029]FIG. 8 is a plan view of an end of a spinneret for spinning therecurrent reflective filament yarn according to the present invention;and

[0030]FIG. 9 illustrates a perspective view of the recurrent reflectivefilament yarn according to the present invention, and a sectional viewtaken in the direction of the arrows along the line A-A′ of therecurrent reflective filament yarn.

DETAILED DESCRIPTION OF THE INVENTION

[0031] Reference will now be made in detail to the present preferredembodiments of the present invention, examples of which are illustratedin the accompanying drawing.

[0032] A recurrent reflective synthetic filament yarn according to thepresent invention is characterized in that it includes 5 to 25 wt %glass beads in which ¼ to ½ of a surface area of the glass beads arevacuum-metalized with a material having reflective function.

[0033] Additionally, the present invention provides the recurrentreflective synthetic filament yarn including 5 to 25 wt % glass beads inwhich ¼ to ½ of the surface area of the glass beads are vacuum-metalizedwith the material having the reflective function, characterized in thatsuch glass beads are aligned so that metalized parts of the glass beadsall point in the same direction.

[0034] Furthermore, the present invention provides a method of producingthe recurrent reflective synthetic filament yarn, includingvacuum-metalizing the material having the reflective function onsurfaces of the spherical glass beads with a bead size of 30 to 50 μmand a refractive index of 1.5 to 2.2 such that ¼ to ½ of surface areasof the spherical glass beads are vacuum-metalized with the materialhaving the reflective function, and melt-spinning the resulting glassbeads in conjunction with a synthetic resin having a fiber formativefunction (hereinafter, referred to as “synthetic fiber resin”) aftersuch glass beads are uniformly mixed with the synthetic fiber resin, ormelt-spinning such glass beads and the synthetic fiber resin mixed witheach other while a spun filament yarn passes through an electric fieldto align the glass beads contained in the filament yarn so thatmetalized parts of the glass beads all point in the same direction,before the spun filament yarn is solidified.

[0035] The recurrent reflective synthetic filament yarn according to thepresent invention has a structure that the spherical glass beads 20vacuum-metalized with the material having the reflective function areuniformly dispersed in the filament yarn 10 as shown in FIGS. 3 to 5, oralternatively, has a structure that the metalized parts 22 of thespherical glass beads 20 vacuum-metalized with the material having thereflective function all point in the same direction as shown in FIG. 6.

[0036] Particularly, in the case of the recurrent reflective syntheticfilament yarn 10 in which the metalized parts 22 of the spherical glassbeads 20 all point in the same direction as shown in FIG. 6, themetalized parts 22 of the glass beads 20 all face in a directionperpendicular to an axis of the filament yarn 10, thus when aunidirectional beam such as light irradiated from the front lights ofautomobiles is irradiated to the filament yarn 10, all of the glassbeads 20 retroreflect the light in the same direction.

[0037] The metalized glass beads 20, a part of the surface of which isvacuum-metalized with the material having the reflective function,should take a shape of a sphere so that the irregular reflection andrecurrent reflection occur in a slit thread produced using the metalizedglass beads 20, thereby an effect of the reflection is sufficientlyachieved.

[0038] The glass beads 20, 40 useful in the present invention are 30 to50 μm in terms of the bead size. For example, when the bead size is lessthan 30 μm, recurrent reflection and irregular reflection effects aregood, the glass beads 20, 40 are easily mixed with the synthetic fiberresin because the glass beads are sufficiently compatible with thesynthetic fiber resin, and the dispersibility and lubricating abilityare not largely reduced. However, it is difficult and not economical toproduce the glass beads with the low bead size while each of the glassbeads maintains a spherical shape. On the other hand, when the bead sizeis more than 50 μm, the slit thread produced using the glass beads istoo thick, the glass beads are not sufficiently mixed with the syntheticfiber resin because the glass beads are not sufficiently compatible tothe synthetic fiber resin, and the dispersibility and lubricatingability are greatly reduced, and thus it is difficult to produce yarnusing the glass beads.

[0039] Furthermore, it is preferable that the refractive index of eachglass bead is 1.5 to 2.2. The reason for this is that the optimumrefractive index of the glass bead is preferably determined inconformity to a refractive index of the synthetic fiber resin 30 becausewhen the light is irradiated to the synthetic fiber resin 30, the lightis refracted by the synthetic fiber resin 30, advances into the glassbeads 20, is reflected by the metalized parts 22 of the glass beads 20,and passes through the synthetic fiber resin 30. Accordingly,illustrative, but non-limiting components of the glass bead include 10to 15% of TiO₂ (titanium dioxide) and BaO (barium oxide) and 85 to 90%of SiO₂ (silicon oxide).

[0040] As described above, the glass beads of the present invention arepartially vacuum-metalized with the material having the reflectivefunction on surfaces thereof. In this respect, the material having thereflective function may be made of highly pure metal materials such astitanium, chromium, silver, or aluminum. In consideration of reflectionefficiency, specific weight, ease of metalization, metalizationproperty, and particularly conductivity and economic efficiency, it ismost preferable to use aluminum as the material having the reflectivefunction.

[0041] The metalized parts of the glass beads vacuum-metalized with thematerial having the reflective function act as a reflective film toretroreflect the light. Accordingly, the “reflective film” means the“metalized parts” of the glass beads, which are formed byvacuum-metalizing ¼ to ½ of surface areas of the spherical glass beadswith the material having the reflective function. In the case of usingonly non-metalized glass beads, the reflective index of each glass beadis 10 to 20 cd/lx·m². On the other hand, in the case of using the glassbeads of which the surfaces are partially vacuum-metalized withaluminum, the reflective index is 450 to 600 cd/lx·m², and average 500to 550 cd/lx·m².

[0042] The reflective film may be formed on the surfaces of the glassbeads with the use of the material having the reflective functionaccording to various Vacuum Metalization processes such as VacuumMetalization, Ion Plating, Sputtering, Vapor Plating, Evaporation,Ion-beam, Molecular Beam Epitaxy, and ARE. As will be appreciated bythose skilled in the art, the reflective film, in particular, thealuminum reflective film can be easily formed on the glass beads. Forexample, a polyethylene terephthalate (PET) sheet is coated withpolyethylene to a thickness of 2 to 25 μm and then a silane siliconecoating agent in an amount of two to five g/m². The glass beads areuniformly dispersed on the resulting PET sheet with the use of avibrator, and thereafter, the glass beads are sunk by a heat roller to ¾to ½ volume into the resulting PET sheet. Finally, the glass beads aremetalized with aluminum in conformity to a predeterminedvacuum-metalizing process, thereby accomplishing the aluminum metalizedparts of the glass beads reflecting the light.

[0043] Additionally, it is preferable that the metalized parts 22 of themetalized glass beads 20 occupy ¼ to ½ of the entire surface area of theglass beads. For example, when the surface area of the metalized part isless than ¼ of the entire glass beads surface area, the reflective indexis reduced because a percentage of light reflected as the recurrentreflection is small, and breakage of yarn easily occurs because a greatnumber of glass beads are used to obtain the sufficient reflectiveindex, and because mostly only the irregular reflection occurs.Furthermore, the filament yarn produced using the glass beads has poortexture and is insufficiently competitive in terms of production costs.On the other hand, when the surface area of the metalized part is morethan ½ of the entire glass beads surface area, the reflective filmcannot be easily formed, the reflective index is reduced because anamount of the retroreflected light is small, and the expense to metalizethe glass beads is large, thus the glass beads of which the metalizedpart occupies an area more than ½ of the entire glass bead surface areaare not economical to use in the production of the filament yarn.

[0044] It is effective to use the metalized glass beads 20 in an amountof 5 to 25 wt % to produce the filament yarn. For example, when anamount of the metalized glass beads 20 is less than 5 wt %, a reflectioneffect cannot be sufficiently obtained. On the other hand, when theamount is more than 25 wt %, an improvement of the reflection effect bythe excessive amount of the metalized glass beads 20 is a little.

[0045] Meanwhile, the synthetic fiber resin may be made of any syntheticresin with fiber formative function, and illustrative, but non-limitingexamples of the synthetic fiber resin used in the present inventioninclude polyester, polyamide (Nylon), vinylon, acryl, polyolefin, vinylchloride, vinylidene chloride, and urethane.

[0046] A dispersing agent and a softner are used so as to prevent areduction of dispersibility of the glass beads 20 in the synthetic fiberresin 30 during a melt-spinning step because the metalized glass beads20 and non-metalized glass beads 40 are incompatible with the syntheticfiber resin 30, and because it is difficult to produce the filament yarnusing the glass beads due to its poor softness. In other words, themetalized glass beads 20 have three to five times higher specific weightthan the synthetic fiber resin 30, that is, the specific weight of themetalized glass beads 20 is 4.2, thus 0.2 to 0.5 wt % softner is addedto the synthetic fiber resin 30 to uniformly mix the glass beads 20 withthe synthetic fiber resin 30, to provide softness to the synthetic fiberresin 30, and to improve the softness of the filament yarn produced withthe use of the glass beads 20 and synthetic fiber resin 30. Furthermore,0.2 to 0.5 wt % dispersing agent is added to the synthetic fiber resinto uniformly mix the metalized glass beads 20 with the synthetic fiberresin 30 in an extruder.

[0047] Any softner and dispersing agent generally used in the art may beused to produce the filament yarn according to the present invention,and it is most preferable that dioctyl phthalate (DOP) is used as thesoftner and Ca antiadditive is used as the dispersing agent. If anamount of the softner or the dispersing agent deviates from a range of0.2 to 0.5 wt %, a desired effect is insufficiently secured or anaddition effect of the softner or the dispersing agent into thesynthetic fiber resin is not greatly improved, thus use of the softneror the dispersing agent is not economical, and physical properties ofthe filament yarn produced using the glass beads and synthetic fiberresin are reduced.

[0048] Further, 0.2 to 0.5 wt % various performance improvers such as aUV shielding agent, an antistatic agent, an aromatic agent, an odorremoving agent, and a deodorant may be additionally used to produce thefilament yarn in order to improve various physical properties of thefilament yarn, and to improve economic efficiency.

[0049] According to the present invention, only the metalized glassbeads 20 may be used to improve the desired reflection effect, but anyone of the non-metalized glass beads 40 and/or pearl beads 50, or acombination thereof may be used in conjunction with the metalized glassbeads 20 to further improve the reflection effect. In this respect, itis preferable that a material of the non-metalized glass beads 40 is thesame as that of the metalized glass beads 20. When the non-metalizedglass beads 40 are added to the synthetic fiber resin 30, the light isrefracted by the non-metalized glass beads 40. When the refracted lightis irradiated into a non-metalized part 21 of the metalized glass beads20, the recurrent reflection occurs by the metalized part 22 of themetalzied glass beads 20, thereby the filament yarn has an improvedreflection effect. As for the pearl beads 50, they are used as areflector with a diameter of 30 to 50 μm. The pearl beads 50 have poorerreflection brightness than the metalized glass beads 20. However, whenthe pearl beads 50 are used in conjunction with the metalized glassbeads 20, they have the desired reflection effect and can show variouscolors with the use of various pigments, thereby they can be used invarious applications. For example, the pearl beads can sufficiently showcombined colors of red, yellow, blue, black, and white etc., thus it isuseful in clothes, bags, and footwear applications. Meanwhile, it ispreferable that a total amount of the metalized glass beads 20, thenon-metalized glass beads 40, and/or the pearl beads 50 added to thesynthetic fiber resin 30 is not more than 35 wt %. If the total amountis more than 35 wt %, the formation of the filament yarn is not smoothlyconducted due to a physical properties difference between the glassbeads and the synthetic fiber resin, and there are several disadvantagesof breakage of the yarn, difficulties of the spinning of a mixture ofthe glass beads and synthetic fiber resin, and the reduction of thephysical properties, such as tensile strength, of the filament yarnproduced using the glass beads. Additionally, it is preferable to usethe spherical non-metalized glass beads 40 to secure the desiredreflection effect.

[0050] A detailed description will be given of a method of producing therecurrent reflective synthetic filament yarn including the glass beads20, below.

[0051] 5 to 25 wt % spherical glass beads having the bead size of 30 to50 μm and the refractive index of 1.5 to 2.2, of which ¼ to ½ of thesurface areas are vacuum-metalized with the material having thereflective function, are melt-spun in conjunction with the syntheticfiber resin to produce the omnidirectional reflective yarn structuredsuch that the glass beads 20 are uniformly distributed in the recurrentreflective synthetic filament yarn 10 as shown in FIG. 3.

[0052] Additionally, when the recurrent reflective synthetic filamentyarn is melt-spun, it passes through an electric field to properlyrotate the glass beads 20 vacuum-metalized with the material having thereflective function so that the metalized parts 22 of the glass beads 20all point in the same direction, before the filament yarn is solidified,thereby producing the recurrent reflective synthetic filament yarnaccording to the present invention, in which the glass beads 20 arealigned so that the metalized parts 22 of the glass beads 20 all pointin the same direction, as shown in FIG. 6.

[0053] In detail, as shown in FIG. 7, when the synthetic fiber resin andglass beads are mixed with each other and then melt-spun through aspinneret 11, a negative plate 12 and a positive plate 13 are installedin such a way that the negative and positive plates 12, 13 face to eachother. The unsolidified filament yarn 10 containing the glass beads 20spun through the spinneret 11 passes through between the positive andnegative plates 13, 12, and a direct current source is connected to thenegative and positive plates 12, 13 to form the electric field aroundthe filament yarn 10, thereby the glass beads 20 are aligned so that themetalized parts 22 of the glass beads 20 all point in the samedirection. When the electric field is formed around the filament yarn20, free electrons in a metal material of the metalized parts 22 of theglass beads 20 are moved toward the positive plate 13, thus polarizingthe glass beads 20, thereby the glass beads 20 ensure an induced dipolemoment.

[0054] The induced dipole moment leads to the alignment of the freeelectrons in the electric field toward a positive pole, thus when amixture of the semi-liquid synthetic fiber resin 30 and glass beads 20is discharged through the spinneret 11, the glass beads 20 sufficientlyrotate in the semi-liquid synthetic fiber resin 30, thereby allowing allof the metalized parts 22 of the glass beads 20 to point in the samedirection. According to the present invention, it is preferable that arelatively high DC (direct current) voltage of 3000 to 20000 V and arelatively low current of three to five mA are applied to the negativeand positive plates 12, 13 and a distance between the negative andpositive plates 12, 13 is one to five mm so as to generate the desiredinduced dipole moment.

[0055] With reference to FIG. 8, there is illustrated a plan view of anend of the spinneret 11 for spinning the recurrent reflective filamentyarns 10 according to the present invention, in which a plurality ofnozzle holes are formed in one row or two rows. The reason why thenozzle holes are aligned in one or two rows is that when the filamentyarns 10, spun through the nozzle holes aligned in one or two rows, passbetween the positive and negative plates 13, 12 while the filament yarns10 being spaced from the positive and negative plates 13, 12 at the sameinterval, the glass beads 20 in the filament yarns 10 are evenlyaffected by the electric field.

[0056] Referring to FIG. 9, there is illustrated the recurrentreflective filament yarns according to the present invention. At thistime, 18 plies of filaments form one yarn. As illustrated in a sectionalview taken in the direction of the arrows along the line A-A′ of theyarn, all of the glass beads 20 are not aligned in the desired directioneffective to the recurrent reflection (in the spinning direction of thefilament yarns), but a portion of glass beads 20 aligned in the desireddirection effective to the recurrent reflection contribute to therecurrent reflection of the filament yarn.

[0057] Accordingly, the filament yarns of the present invention, inwhich the metalized parts 22 of the glass beads 20 point in the samedirection, act as the recurrent reflective yarn, and if the filamentyarns of the present invention are mixed with other filament yarns, thelight recurrently reflected by the filament yarn of the presentinvention is again recurrently reflected by the other filament yarns,thereby realizing an omnidirectional reflection effect.

[0058] A better understanding of the present invention may be obtainedin light of the following examples which are set forth to illustrate,but are not to be construed to limit the present invention.

EXAMPLE 1

[0059] To produce polypropylene (PP) filament yarn having theomnidirectional reflection function, ⅓ of a surface area of glass beadswith an average bead size of 40 μm and a bead size distribution of 30 to50 μm was vacuum-metalized with aluminum to produce metalized glassbeads. 85 wt % polypropylene resin was added in conjunction with 0.5 wt% dioctylphthalate based on the polypropylene resin into a stirrer, thenstirred at a rotation speed of 100 rpm for 30 min to form a thin oilfilm on a surface of the polypropylene resin. 15 wt % metalized glassbeads were added into the stirrer and stirred at the rotation speed of100 rpm for 30 min. At this time, the metalized glass beads wereuniformly distributed on the surface of the polypropylene resin by oilcomponents of the oil film formed on the surface of the polypropyleneresin. The resulting resin including the glass beads according to thepresent invention may be melt-spun without a traditional master batch.In the present invention, production costs of the polypropylene filamentyarn are relatively low because it is not necessary to produce themaster batch, and a transparent slit thread is produced because thedegradation of the polypropylene resin caused by the extrusion forproducing the master batch is prevented. The resulting polypropyleneresin including the glass beads was melt-spun using an extruder at 210□at an extruding speed of 600 to 800 m/min to produce an undrawn filamentyarn of 430 deniers/18 filaments, then drawn 2.3 times longer by use ofa drawing machine to produce a drawn filament yarn of 180 deniers withtenacity of 3 g/denier.

EXAMPLE 2

[0060] To produce a polyester (PET) filament yarn having theomnidirectional reflection function, a polyethylene terephthalate resinwith an intrinsic viscosity of 0.77 and the metalized glass beads ofexample 1 were sufficiently dried in two different driers, respectively,for 10 hours so that moisture contents reached 25 ppm or lower. Thedried metalized glass beads were added through a side feeder into anextruder in an amount of 15 wt % while the dried polyethyleneterephthalate resin was discharged from the extruder at 285□ at anextruding speed of 600 to 800 m/min to produce undrawn filament yarn of450 deniers/18 filaments. The undrawn filament yarn was then drawn 2.1times longer by use of a drawing machine to produce a drawn filamentyarn of 200 deniers with tenacity of 3.0 g/denier.

EXAMPLE 3

[0061] To produce a PET filament yarn having the omnidirectionalreflection function, a polyethylene terephthalate resin with theintrinsic viscosity of 0.77 and the metalized glass beads of example 1were sufficiently dried in two different driers, respectively, for 10hours so that moisture contents reached 25 ppm or lower. The driedmetalized glass beads were then added through a side feeder into anextruder in an amount of 15 wt % while the dried polyethyleneterephthalate resin was discharged from the extruder at 285□, then drawn2.1 times longer by use of two pairs of hot godet rollers to produce adrawn filament yarn of 200 deniers with tenacity of 3.0 g/denier.

EXAMPLE 4

[0062] To produce a polyamide (nylon) filament yarn having theomnidirectional reflection function, dried metalized glass beads wereuniformly added through a side feeder into an extruder in an amount of15 wt % while nylon chips with a relative viscosity of 2.4 weredischarged through the extruder at 265□ to produce a polyamide filamentyarn of 180 deniers/18 filaments.

EXAMPLES 5 TO 8

[0063] Procedures of examples 1 to 4 were repeated except thatnon-metalized glass beads were additionally added to a synthetic fiberresin in the amount of 5 wt %, thereby synthetic filament yarns wereproduced. The synthetic filament yarns thus produced had an improvedreflection effect, and the reflection effect of light depended on theamount of the metalized and/or non-metalized glass beads in thesynthetic filament yarns, thus various synthetic filaments yarns may beproduced according to consumer needs by controlling the amount of themetalized and/or non-metalized glass beads in the synthetic filamentyarns.

EXAMPLE 9

[0064] An undrawn filament yarn melt-spun according to the sameprocedure as example 1 was drawn by use of a drawing machine andsimultaneously cut to produce staple fibers having mono fineness of 7denier and length of 52 mm. Then, the staple fibers thus produced wereheat-treated with the use of a calender roll at 145□ to producenon-woven fabrics with a thickness of 0.13 mm. Alternatively, thenon-woven fabrics were produced with the use of the staple fibersaccording to a conventional heat fusion process, as in a conventionalfiber production process, and the non-woven fabrics were suitable to useas the alternative of PET based rigid reflective clothes and had goodworkability. The non-woven fabrics were advantageous in that they weresuitable to use as a very soft fiber, in comparison with a conventionalPET sheet, (both sides of the sheet were coated with an aluminumreflector and glass beads, respectively, to have the recurrentreflection function), or a conventional PVC sheet, thus the non-wovenfabrics can be extensively applied to various applications such assafety clothing or safety signs.

EXAMPLES 10 TO 18

[0065] Procedures of examples 1 to 9 were repeated except that thenon-metalized glass beads were uniformly mixed with the pearl beads in aweight ratio of 70:30 and the resulting mixture was added through a sidefeeder in conjunction with yellow pigment master chips into an extruderin a proportion of 2 wt %, to produce yarn-died synthetic filament yarnswith yellow and pearl colors.

EXAMPLE 19

[0066] To produce polypropylene (PP) filament yarn having the recurrentreflection function, ⅓ of surface area of spherical glass beads with anaverage bead size of 40 μm, a refractive index of 1.5 to 2.2, and a beadsize distribution of 30 to 50 μm was vacuum-metalized with aluminum toproduce metalized glass beads. 85 wt % polypropylene resin was added inconjunction with 0.5 wt % dioctylphthalate based on the polypropyleneresin into a stirrer, then stirred at a rotation speed of 100 rpm for 30min to form a thin oil film on a surface of the polypropylene resin. 15wt % metalized glass beads were added into the stirrer and stirred atthe rotation speed of 100 rpm for 30 min. At this time, the metalizedglass beads were uniformly distributed on the surface of thepolypropylene resin by oil components of the oil film formed on thesurface of the polypropylene resin. The resulting polypropylene resinincluding the glass beads was melt-spun using an extruder at 210□ at anextruding speed of 600 to 800 m/min and simultaneously passed through anelectric field around a spinneret (refer to FIG. 7) before filamentsspun from the extruder were solidified to produce an undrawn filamentyarn of 430 deniers/18 filaments. The undrawn filament yarn was drawn2.3 times longer by use of a drawing machine to produce a drawn filamentyarn of 180 deniers with tenacity of 3 g/denier.

EXAMPLE 20

[0067] To produce a polyester (PET) filament yarn having the recurrentreflection function, a polyethylene terephthalate resin with anintrinsic viscosity of 0.77 and the metalized glass beads of example 19were sufficiently dried in two different driers, respectively, for 10hours so that moisture contents reached 25 ppm or lower. The driedmetalized glass beads were added through a side feeder into an extruderin an amount of 15 wt % while the dried polyethylene terephthalate resinwas discharged from the extruder at 285□ at an extruding speed of 600 to800 m/min and simultaneously passed through an electric field around aspinneret before filaments spun from the extruder were solidified toproduce an undrawn filament yarn of 450 deniers/18 filaments. Theundrawn filament yarn was then drawn 2.1 times longer by use of adrawing machine to produce a drawn filament yarn of 200 deniers withtenacity of 3.0 g/denier.

EXAMPLE 21

[0068] To produce a PET filament yarn having the recurrent reflectionfunction, a polyethylene terephthalate resin with the intrinsicviscosity of 0.77 and the metalized glass beads of example 19 weresufficiently dried in two different driers, respectively, for 10 hoursso that moisture contents reached 25 ppm or lower. The dried metalizedglass beads were then added through a side feeder into an extruder in anamount of 15 wt % while the dried polyethylene terephthalate resin wasdischarged from the extruder at 285μ. The resulting resin spun from theextruder passed through an electric field around a spinneret before theresulting resin spun from the extruder were solidified to producefilaments. The filaments were drawn 2.1 times longer by use of two pairsof hot godet rollers to produce a drawn filament yarn of 200 denierswith tenacity of 3.0 g/denier.

EXAMPLE 22

[0069] To produce a polyamide (nylon) filament yarn having the recurrentreflection function, dried metalized glass beads were uniformly addedthrough a side feeder into an extruder in an amount of 15 wt % whilenylon chips with a relative viscosity of 2.4 were discharged through theextruder at 265□. Filaments spun from the extruder passed through anelectric field around a spinneret before the filaments spun from theextruder were solidified to produce a polyamide filament yarn of 180deniers/18 filaments.

[0070] As described above, the present invention provides a recurrentreflective synthetic filament yarn including 5 to 25 wt % sphericalglass beads each having a bead size of 30 to 50 μm and a refractiveindex of 1.5 to 2.2 and vacuum-metalized with a material having thereflection function such that ¼ to ½ of an entire surface area of theglass beads are vacuum-metalized. In this respect, the glass beads arealigned so that metalized parts of the glass beads all point in the samedirection. Therefore, the recurrent reflective synthetic filament yarnof the present invention acts as a yarn while securing almost the samereflection efficiency as a conventional slit film or a conventional slitthread. In the production of the conventional film or thread, after analuminum paste layer as a reflective layer is coated on any one side ofa thin synthetic resin film or sheet, a mixture of transparentpolyurethane or an adhesive and the glass beads is coated on thealuminum paste layer to produce the reflective film or sheet, and thereflective film or sheet thus produced is longitudinally slit in such away that a width of the reflective film or sheet is 0.25 to 0.37 mm inthe case of the narrow reflective film or sheet, or 3 to 5 mm in thecase of the wide reflective film or sheet. At this time, theconventional slit reflective film or sheet is doubled or twisted with asynthetic yarn to produce the slit thread.

[0071] Accordingly, the recurrent reflective synthetic filament yarn ofthe present invention has superior texture and improved workability, andcan be applied to a mechanical embroidery, a computer embroidery, and asewing process because the recurrent reflective synthetic filament yarncan be used as an embroidery yarn. Furthermore, it has the superiorcolor fastness to washing and the washing of the filament yarn can beeasily conducted. As well, the filament yarn is not changed after thewashing in views of the physical properties, applied to variousapplications, produced in commercial quantity, and very competitive interms of production costs.

[0072] In the following table 1, there are described brightnesses ofwoven fabrics, produced using the filaments of examples 19 to 22 of thepresent invention, according to an Europe EN471 standard, and thebrightnesses of the woven fabrics in the case of using the desirablyaligned glass beads are compared with those of the woven fabrics in thecase of using the glass beads without being aligned. The measurement oflight is conducted under conditions of an incidence angle of 5 degreesand an observation angle of 0.2 degrees. TABLE 1 Reflection performance{cd/(lux · m²)} Desirably aligned Non-aligned Example glass beads glassbeads 19 280 130 20 250 100 21 260 120 22 240 90

[0073] From the table 1, it can be seen that the brightness of the wovenfabric in the case of using the glass beads desirably aligned in eachfilament is improved by 100% or more in comparison with that of thewoven fabric in the case of using the glass beads without being aligned.

[0074] The present invention has been described in an illustrativemanner, and it is to be understood that the terminology used is intendedto be in the nature of description rather than of limitation. Manymodifications and variations of the present invention are possible inlight of the above teachings. Therefore, it is to be understood thatwithin the scope of the appended claims, the invention may be practicedotherwise than as specifically described.

What is claimed is:
 1. A recurrent reflective synthetic filament yarnproduced by the following process including the steps of: melt-spinninga mixture of glass beads and a synthetic fiber resin through aspinneret, said beads being vacuum-metalized with a material having areflection function; positioning an electric field around the spinneret;and passing said filament through the electric field before saidfilament is solidified, whereby said glass beads in said filament rotateso that said metalized parts of the glass beads all point in a samedirection.
 2. The yarn of claim 1, wherein said yarn filament comprisessubstantially 5 to 25 wt % of said glass beads.
 3. The yarn of claim 1,wherein each of the glass beads is a spherical shape having a bead sizeof 30 to 50 μm, and a refractive index of 1.5 to 2.2.
 4. The yarn ofclaim 1, wherein the material having the reflective function is selectedfrom the group consisting of aluminum, nickel, and silver.
 5. Arecurrent reflective synthetic filament yarn; said filament includingvacuum-metalizing spherical glass beads each having a bead size of 30 to50 μm and a refractive index of 1.5 to 2.2, wherein ¼ to ½ of an entiresurface area of the spherical glass beads are vacuum-metalized with amaterial, said material having a reflection function; said filamentincluding a synthetic resin; wherein 5 to 25 wt % of said filament issaid glass beads and 95 to 75 wt % of said filament is said syntheticfiber resin; wherein said filament is melt-spun through a spinneret;said yarn produced by the following method including the steps of:passing said filaments through an electric field around the spinneretbefore said filaments are solidified, so as to rotate the glass beadscontained in the filaments such that metalized parts of the glass beadsall point in a same direction.
 6. The yarn of claim 5 wherein saidspinneret having a nozzle and nozzle holes, said method comprising thesteps of: installing a positive plate and a negative plate under thenozzle holes of the spinneret such that the positive plate and thenegative plate face each other and are spaced from each other at aninterval of one to five mm; and applying a voltage of 3000 to 20000 Vand a current of three to five mA to the positive plate and negativeplate, thereby forming the electric field.
 7. The yarn of claim 6,wherein the nozzle holes of the spinneret are aligned in one or tworows.
 8. The yarn of claim 5, wherein the method comprising the stepsof: adding 0.2 to 0.5 wt % of dioctylphthalate as a softener and 0.2 to0.5 wt % of Ca antiadditive as a dispersing agent into the syntheticfiber resin to uniformly mix the glass beads with the synthetic fiberresin, to provide softness to the synthetic fiber resin during themelt-spinning of a mixture of the glass beads and synthetic fiber resin,and to improve the softness of the recurrent reflective syntheticfilament yarn.
 9. The yarn of claim 6, wherein the method comprising thesteps of: adding 0.2 to 0.5 wt % of dioctylphthalate as a softener and0.2 to 0.5 wt % of Ca antiadditive as a dispersing agent into thesynthetic fiber resin to uniformly mix the glass beads with thesynthetic fiber resin, to provide softness to the synthetic fiber resinduring the melt-spinning of a mixture of the glass beads and syntheticfiber resin, and to improve the softness of the recurrent reflectivesynthetic filament yarn.